Multitier Arrangements of Integrated Devices, and Methods of Forming Sense/Access Lines

ABSTRACT

Some embodiments include an arrangement having a memory tier with memory cells on opposing sides of a coupling region. First sense/access lines are under the memory cells, and are electrically connected with the memory cells. A conductive interconnect is within the coupling region. A second sense/access line extends across the memory cells, and across the conductive interconnect. The second sense/access line has a first region having a second conductive material over a first conductive material, and has a second region having only the second conductive material. The first region is over the memory cells, and is electrically connected with the memory cells. The second region is over the conductive interconnect and is electrically coupled with the conductive interconnect. An additional tier is under the memory tier, and includes CMOS circuitry coupled with the conductive interconnect. Some embodiments include methods of forming multitier arrangements.

TECHNICAL FIELD

Multitier arrangements of integrated devices, and methods of formingsense/access lines.

BACKGROUND

Efforts are being directed toward forming multitier arrangements ofintegrated devices. For instance, a tier comprising memory may be formedover a tier comprising drivers, sense amplifiers, etc. It may be desiredto form sense/access lines (e.g., bitlines) which are coupled withmemory devices of the upper tier, and which are also coupled withcomponents of the lower tier through interconnects that extend throughthe upper tier. It would be desirable to develop structures specificallyconfigured to be suitable for such applications, and to develop methodsof forming such structures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross-sectional side view of an exampleassembly comprising an example arrangement of memory cells.

FIG. 1A is a diagrammatic top view of a region of the assembly ofFIG. 1. The cross-section of FIG. 1 is along the line 1-1 of FIG. 1A.

FIG. 1B is a diagrammatic cross-sectional side view of an example memorycell which may be utilized instead of the example memory cells shown inFIG. 1.

FIG. 2 is a diagrammatic cross-sectional side view of an examplemultitier configuration.

FIG. 3 is a diagrammatic top view of a region of the assembly of FIG. 1illustrating the wordlines and bitlines in isolation from othercomponents.

FIG. 4 is a diagrammatic schematic view of an example memory array.

FIG. 5 is a diagrammatic cross-sectional side view of an assembly at anexample process stage of an example embodiment.

FIG. 6 is a diagrammatic cross-sectional side view of the assembly ofFIG. 5 at an example process stage following that of FIG. 5.

FIG. 6A is a diagrammatic top view of a region of the assembly of FIG.6. The cross-section of FIG. 6 is along the line 6-6 of FIG. 6A.

FIG. 7 is a diagrammatic cross-sectional side view of the assembly ofFIG. 5 at an example process stage following that of FIG. 6.

FIG. 8 is a diagrammatic cross-sectional side view of the assembly ofFIG. 5 at an example process stage following that of FIG. 7.

FIG. 9 is a diagrammatic cross-sectional side view of the assembly ofFIG. 5 at an example process stage following that of FIG. 8.

FIG. 9A is a diagrammatic top view of a region of the assembly of FIG.9. The cross-section of FIG. 9 is along the line 9-9 of FIG. 9A.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Some embodiments include multitier architectures in which a memory tieris over a tier comprising CMOS circuitry, and in which components of thememory tier are electrically coupled with the CMOS circuitry throughconductive interconnects. In some embodiments, sense/access lines (e.g.,bitlines) may extend across the memory cells and the conductiveinterconnects, and may have different compositional configurations overthe memory cells than over the conductive interconnects. In someapplications, regions of the sense/access lines which are over anddirectly against the conductive interconnects will have lower resistance(i.e., higher conductivity) than regions which are over and directlyagainst electrodes of the memory cells. Some embodiments include methodsof forming multitier architectures. Example embodiments are describedwith reference to FIGS. 1-9.

Referring to FIG. 1, an assembly 10 shows an example configuration forcoupling a bitline (50) to memory cells (12) and a conductiveinterconnect (46).

The assembly 10 includes a memory array 11, which comprises the memorycells 12. The memory cells 12 are supported by wordlines (access lines)14. The illustrated memory cells 12 may be representative of a largenumber of substantially identical memory cells within the memory array11; and in some embodiments the memory array 11 may comprise hundreds,thousands, millions, hundreds of millions, etc., of the memory cells.The term “substantially identical” means identical to within reasonabletolerances of fabrication and measurement. The illustrated wordlines 14may be representative of a large number of substantially identicalwordlines within the memory array.

The wordlines 14 comprise conductive material 16. The conductivematerial 16 may comprise any suitable electrically conductivecomposition(s); such as, for example, one or more of various metals(e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium, etc.),metal-containing compositions (e.g., metal silicide, metal nitride,metal carbide, etc.), and/or conductively-doped semiconductor materials(e.g., conductively-doped silicon, conductively-doped germanium, etc.).In some embodiments, the conductive material 16 may comprise one or moremetals and/or metal-containing compositions; and may, for example,comprise tungsten over tantalum nitride.

Each of the memory cells 12 comprises a bottom electrode 18, a topelectrode 20, and a programmable material 22 between the top and bottomelectrodes. The electrodes 18 and 20 comprise conductive electrodematerials 24 and 26, respectively. The electrode materials 24 and 26 maycomprise any suitable electrically conductive composition(s); such as,for example, one or more of various metals (e.g., titanium, tungsten,cobalt, nickel, platinum, ruthenium, etc.), metal-containingcompositions (e.g., metal silicide, metal nitride, metal carbide, etc.),and/or conductively-doped semiconductor materials (e.g.,conductively-doped silicon, conductively-doped germanium, etc.). Theelectrode materials 24 and 26 may be the same composition as oneanother, or may be of different compositions relative to one another. Insome example embodiments, the electrode materials 24 and 26 maycomprise, consist essentially of, or consist of one or more of TiSiN(titanium silicon nitride), TiAlN (titanium aluminum nitride), TiN(titanium nitride), WN (tungsten nitride), Ti (titanium), C (carbon) andW (tungsten); where the formulas indicate the components within thelisted substances, rather than designating specific stoichiometries ofsuch components.

The bottom electrodes 18 are electrically coupled with the wordlines 14,and in the shown embodiment are directly against the wordlines.

The programmable material 22 may comprise any suitable composition(s).In some embodiments, the programmable material 22 may be an ovonicmemory material, and specifically may be a chalcogenide. For instance,the programmable material 22 may comprise one or more of germanium (Ge),antimony (Sb), tellurium (Te) and indium (In). In specific embodiments,the programmable material 22 may, for example, comprise, consistessentially of, or consist of GeSbTe or InGeTe, where the formulasindicate the components within the listed substances, rather thandesignating specific stoichiometries of such components. In someembodiments, the memory cells may comprise programmable materialconfigured to be utilized in self-selecting devices; for example, achalcogenide material may act both as a storage element and as a selectdevice. The chalcogenide may be utilized alone in the self-selectingdevice, or may be utilized in combination with another composition.Example self-selecting PCM devices (with PCM devices being devicescomprising phase change material) are described in U.S. Pat. No.8,847,186 (Redaelli et al.) and U.S. Pat. No. 10,134,470 (Tortorelli etal.), listing Micron Technology, Inc. as the assignee.

The memory cells 12 are example memory cells which may be utilized in amemory array. In other embodiments, the memory cells may have otherconfigurations. For instance, FIG. 1B shows a memory cell 12 a havinganother example configuration. The memory cell includes the electrodes18 and 20, and further includes a third electrode 28. In someembodiments, the electrodes 28, 18 and 20 may be referred to as a bottomelectrode, a middle electrode, and a top electrode, respectively. Theelectrode 28 comprises electrode material 30. Such electrode materialmay comprise any of the compositions described above relative to theelectrode materials 24 and 26; and may be the same composition as one orboth of the electrode materials 24 and 26, or may be compositionallydifferent than at least one of the electrode materials 24 and 26.

The ovonic material 22 may be referred to as a first ovonic materialbetween the upper electrode 20 and the middle electrode 18. A secondovonic material 32 is between the lower electrode 28 and the middleelectrode 18. The second ovonic material 32 may be incorporated into anovonic threshold switch (OTS) of a select device 34. The memory cell 12a may thus comprise the programmable material 22 in combination with theselect device 34, rather than being in a self-selecting configuration.

The ovonic material 32 may comprise any suitable composition(s), and insome embodiments may comprise one or more of the compositions describedabove as being suitable for the programmable material 22.

Referring again to FIG. 1, the wordlines 14 may be considered to extendin and out of the page relative to the cross-sectional view. Insulativematerial 40 is between the wordlines, and spaces the wordlines from oneanother. The insulative material 40 also isolates neighboring memorycells 12 from one another. The insulative material 40 may comprise anysuitable composition(s); and in some embodiments may comprise, consistessentially of, or consist of silicon dioxide.

The cross-sectional view of FIG. 1 shows the memory cells 12 arranged toform a first set 36 and a second set 38. A coupling region 42 is betweenthe first and second sets (36, 38) of the memory cells.

An insulative material 44 extends across the coupling region 42. Theinsulative material 44 may comprise any suitable composition(s); and insome embodiments may comprise, consist essentially of, consist ofsilicon dioxide. The insulative material 44 may be referred to as anintervening insulative material in some of the applications describedherein.

The conductive interconnect 46 is within the coupling region 42. Theconductive interconnect comprises conductive material 48. The conductivematerial 48 may comprise any suitable electrically conductivecomposition(s); such as, for example, one or more of various metals(e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium, etc.),metal-containing compositions (e.g., metal silicide, metal nitride,metal carbide, etc.), and/or conductively-doped semiconductor materials(e.g., conductively-doped silicon, conductively-doped germanium, etc.).The conductive interconnect 46 may extend entirely through a tier (i.e.,deck, level, etc.) comprising the memory array 11. The conductiveinterconnect 46 may comprise multiple compositions, and may comprisedifferent compositions at various locations throughout the tier. Theillustrated portion of the conductive interconnect 46 may comprise,consist essentially of, or consist of tungsten in some exampleembodiments.

The memory cells 12 have upper surfaces 15 along the upper electrodes20, and the interconnect 46 has an upper surface 47. The illustratedupper surfaces 15 are planar. In other embodiments, the upper surfaces15 may have other suitable configurations. The illustrated upper surface47 is dome-shaped. In other embodiments, the upper surface 47 may beplanar, or may have any other suitable shape.

The bitline (digit line, sense line) 50 extends across the first andsecond sets (36, 38) of the memory cells 12, and across the conductiveinterconnect 46; and is electrically coupled with the memory cells 12and the conductive interconnect 46. The bitline comprises a first region52 and a second region 54, with such regions being compositionallydifferent than one another. The composition of the first region 52 maybe referred to as a first composition, and the composition of the secondregion 54 may be referred to as a second composition.

In the illustrated embodiment, the first region 52 comprises twomaterials 56 and 58, and the second region 54 only comprises thematerial 58. In other embodiments, the regions 52 and 54 may comprisedifferent numbers of materials than are shown in the example embodimentof FIG. 1. The illustrated materials 56 and 58 may be referred to asfirst and second materials, respectively. In some embodiments, thematerials 56 and 58 may be considered to correspond to first and secondlayers, respectively; or to a lower layer and an upper layer,respectively.

The first material 56 directly contacts the upper surfaces 15 of thememory cells. The first material 56 does not extend to over the uppersurface 47 of the conductive interconnect 46, and instead the secondmaterial 58 directly contacts the upper surface 47.

The conductive interconnect 46 has sidewall surfaces 49; and in theillustrated embodiment the first material 56 directly contacts suchsidewall surfaces. In other embodiments, it may be only the conductivematerial 58 which directly contacts any surfaces of the conductiveinterconnect 46.

In some embodiments, the material 56 may have higher resistivity (i.e.,lower conductivity) than the material 58. The combined materials 56 and58 may be suitable for utilization as a bitline electrically coupledwith the memory cells 12, but it may be desired for the electricalconnection to the conductive interconnect 46 to only utilize thelow-resistivity (high-conductivity) material 58; with the terms“low-resistivity” and “high-conductivity” meaning that the material 58has lower resistivity (lower resistance) and corresponding higherconductivity (higher conductance) than the material 56, rather thanmeaning low-resistivity or high-conductivity in an absolute sense. Thedirect coupling of the interconnect 48 to the low-resistivity material58 may enable enhanced transfer of signals from the bitline 50 to theconductive interconnect 48, which may improve speed and reliabilityrelative to configurations in which the interconnect 46 couples tohigher-resistivity material.

The conductive materials 56 and 58 may comprise any suitablecomposition(s); such as, for example, one or more of various metals(e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium, etc.),metal-containing compositions (e.g., metal silicide, metal nitride,metal carbide, etc.), and/or conductively-doped semiconductor materials(e.g., conductively-doped silicon, conductively-doped germanium, etc.).In some embodiments, the first conductive material 56 comprises,consists essentially of, or consists of one or more of C (carbon), WSiN(tungsten silicon nitride), WN (tungsten nitride) and TiN (titaniumnitride), where the formulas indicate components rather than indicatingspecific stoichiometries; and the second conductive material 58comprises, consists essentially of, or consists of one or more of Ta(tantalum), Pt (platinum), Cu (copper), W (tungsten) and Pd (palladium).

In some embodiments, the first region 52 of the bitline 50 may beconsidered to comprise two or more materials (e.g., the materials 56 and58), and the second region 54 of the bitline may be considered toinclude a subset of the materials of the first region (e.g., comprisesonly the material 58 in the illustrated embodiment).

In some embodiments, the first material 56 may comprise a first metal(e.g., tungsten or titanium) in combination with one or more nonmetallicelements (e.g., one or more of silicon, nitrogen, carbon, etc.); and thesecond material 58 may consist of a second metal (e.g., one or more ofTa, Pt, Cu, W and Pd). The second metal of the material 58 may be thesame as the first metal of the material 56, or may be different than thefirst metal of the material 56. In some specific applications, the firstmaterial 56 may consist of WSiN (where the chemical formula indicatesconstituents rather than a specific stoichiometry), and the secondmaterial 58 may consist of W.

FIG. 1A shows a top view of the assembly 10. The view of FIG. 1A is notto scale relative to the view of FIG. 1, and utilizes a differentdiagrammatic representation of the assembly 10 than is utilized inFIG. 1. Regardless, the cross-section of FIG. 1 may be understood to begenerally along the line 1-1 of FIG. 1A.

The coupling region 42 comprises a plurality of the conductiveinterconnects 46. The conductive interconnects are arranged along a row,with such row extending along a direction which would be in and out ofthe page relative to the plane of the cross-section of FIG. 1. Theconductive interconnects may be circular-shaped in top-down view (asshown), or may have any other suitable shapes, including, for example,square shapes, rectangular shapes, elliptical shapes, etc.

It is to be understood that even though the cross-section of FIG. 1 onlycomprises one of the conductive interconnects 46 within the illustratedportion of the coupling region 42, in other embodiments there may bemultiple conductive interconnects formed along the cross-section ofFIG. 1. Accordingly, even though FIG. 1A shows a single row of theinterconnects 46 within the coupling region 42, in other embodimentsthere may be multiple rows of such interconnects arranged in a matrix orother suitable configuration. Also, it is to be understood that theillustrated interconnects 46 of FIG. 1A may be representative of a largenumber of substantially identical interconnects formed within thecoupling region 42. For instance, in some embodiments there may behundreds, thousands, millions, hundreds of thousands, etc., of theconductive interconnects 46 formed within the coupling region 42.

FIG. 1A shows that a plurality of the bitlines 50 extend across thememory array 11 and the coupling region 42. Each of the bitlines extendsacross one of the illustrated conductive interconnects 46. Theconductive interconnects 46 are shown in dashed-line view in FIG. 1A toindicate that they are under the bitlines 50. The illustrated bitlines50 may be representative of a large number of substantially identicalbitlines associated with the memory array 11. For instance, in someembodiments there may be hundreds, thousands, millions, hundreds ofthousands, etc., of the bitlines 50 associated with the memory array.

The description of FIG. 1 indicates that the wordlines 14 are under thememory cells 12, and that the bitlines 56 are over the memory cells. Inother applications, the relative orientation of the wordlines andbitlines may be reversed so that the bitlines are under the memory cellsand the wordlines are over the memory cells. The terms “access/senseline,” “bitline/wordline,” “wordline/bitline” and “sense/access line”may be utilized herein to generically refer to bitlines and wordlines incontexts in which an indicated structure may be either a wordline or abitline.

The conductive interconnects 46 of FIGS. 1 and 1A may be utilized toenable circuitry from one tier to be electrically coupled with circuitryof another tier within a multitier stack. For instance, FIG. 2 shows amultitier stack 60 having two tiers 62 and 64 in a vertical stack. Thevertically-stacked arrangement of FIG. 2 may extend upwardly to includeadditional tiers. The tiers 62 and 64 may be considered to be examplesof levels that are stacked one atop the other. The levels may be withindifferent semiconductor dies (wafers), or may be within the samesemiconductor die. The bottom tier 62 may include control circuitryand/or sensing circuitry (e.g., may include wordline drivers, senseamplifiers, etc.; and may include CMOS circuitry, as shown). The uppertier 64 may include a memory array, such as, for example, the memoryarray 11 of FIGS. 1 and 1A; and may be referred to as a memory tier.

The conductive interconnect 46 of FIG. 1 is illustrated as enablingelectrical coupling of circuitry associated with the tier 64 tocircuitry associated with the tier 62, with such electrical couplingbeing diagrammatically shown utilizing a dashed arrow 61. In an exampleembodiment, a sense/access line 50 associated with the memory array 11is electrically coupled with circuitry of the tier 62 through theconductive interconnect 46. For instance, a bitline associated with thememory array within the tier 64 may be coupled with a sense amplifierwithin the tier 62 through the connection 61. As another example, awordline associated with memory array within the tier 64 may be coupledwith a wordline driver within the tier 62 through the connection 61.

The memory array 11 of FIGS. 1 and 1A comprises a first series ofsense/access lines 14 extending along a first direction (in and out ofthe page relative to the cross-section of FIG. 1), and a second seriesof sense/access lines 50 extending along a second direction (along aplane of the cross-section of FIG. 1), with the second direction beingorthogonal to the first direction. FIG. 3 shows another diagrammatic topview of the assembly 10 of FIGS. 1 and 1A; and shows the wordlines 14arranged as a first series of sense/access lines under the memory cells12, and the bitlines 50 arranged as a second series of sense/accesslines over the memory cells 12. The memory cells 12 are not visible inFIG. 3, but are to be understood as being at cross-points where thesense/access lines 50 cross the sense/access lines 14 (with a dashedarrow diagrammatically illustrating an example cross-point location of amemory cell 12).

The memory array 11 of FIGS. 1 and 1A may have any suitableconfiguration. FIG. 4 schematically illustrates an example configurationof the memory array 11. Such configuration includes the memory cells 12at cross-points where wordlines (WL1-WL4) pass the bitlines (BL1-BL6).Each of the memory cells is uniquely addressed through a combination ofone of the wordlines and one of the bitlines.

The configuration of FIGS. 1 and 1A may be formed with any suitableprocessing. Example processing is described with reference to FIGS. 5-9.

Referring to FIG. 5, a capping material 66 is over the first and secondsets (36, 38) of the memory cells 12. The capping material 66 maycomprise any suitable composition(s); and in some embodiments maycomprise, consist essentially of, or consist of silicon nitride. Theinsulative material 44 is provided over the capping material 66 andacross the coupling region 42. In some embodiments, the insulativematerial 44 may be considered to extend across an intervening regionbetween the sets 36, 38 of memory cells 12; with such intervening regioncorresponding to the coupling region 42. The memory cells 12 of FIG. 5may be replaced with other memory cells (e.g., memory cells having theconfiguration of the memory cell 12 a of FIG. 1A) in other embodiments.

Referring to FIG. 6, the assembly 10 is shown after formation of theconductive interconnect 46 within the coupling region 42; and after oneor more polishing processes have been utilized to expose the uppersurfaces 15 of the memory cells 12, and the upper surface 47 of theconductive interconnect 46.

The conductive interconnect 46 may be formed with any suitableprocessing. For instance, in some example embodiments a via may beformed to extend through the materials within the coupling region 42,and then suitable conductive material(s) may be provided within the viato form the conductive interconnect 46.

The upper surface 47 of the conductive interconnect 46 projects above anupper surface 45 of the polished material 44. Such may be a naturalconsequence of polishing (e.g., chemical-mechanical polishing, CMP) dueto the relative hardness of the conductive material 48 as compared tothe silicon dioxide 44. The upper surface 47 of the conductiveinterconnect 48 is above the upper surface 45 of the insulative material44 by a height H. Such height may be at least about 10 Å, at least about20 Å, at least about 50 Å, etc.

FIG. 6A shows a top view of the assembly 10 at the processing stage ofFIG. 6 utilizing a diagrammatic illustration analogous to that of FIG.1A. The view of FIG. 6A shows that the conductive interconnect 46 ofFIG. 6 may be one of many substantially identical conductiveinterconnects, with others of the conductive interconnect being formedout of the plane of the cross-section of FIG. 6.

Referring to FIG. 7, the conductive material 56 is formed along an uppersurface of the assembly 10. The conductive material 56 extends acrossthe memory cells 12, and across the conductive interconnect 46; anddirectly contacts the upper surfaces 15 of the memory cells 12, and theupper surface 47 of the conductive interconnect 46.

Referring to FIG. 8, the conductive material 56 is removed from over theupper surface 47 of the conductive interconnect 46, while leavingportions of the conductive material 56 remaining over the memory cells12 of the first and second sets 36 and 38. The conductive material 56may be removed from over the surface 47 with any suitable processing;and in some embodiments is removed with a polishing process (e.g., CMP).

Referring to FIG. 9, the conductive material 58 is formed over theconductive material 56, and the conductive materials 56 and 58 aretogether patterned into a bitline 50. The assembly 10 of FIG. 9comprises the configuration described above with reference to FIG. 1.FIG. 9A shows a top view of the assembly 10 at the processing stage ofFIG. 9 utilizing a diagrammatic illustration analogous to that of FIG.1A. The view of FIG. 9A shows that the bitline 50 is one of manysubstantially identical bitlines which may be fabricated utilizing theprocessing of FIGS. 5-9.

The assemblies and structures discussed above may be utilized withinintegrated circuits (with the term “integrated circuit” meaning anelectronic circuit supported by a semiconductor substrate); and may beincorporated into electronic systems. Such electronic systems may beused in, for example, memory modules, device drivers, power modules,communication modems, processor modules, and application-specificmodules, and may include multilayer, multichip modules. The electronicsystems may be any of a broad range of systems, such as, for example,cameras, wireless devices, displays, chip sets, set top boxes, games,lighting, vehicles, clocks, televisions, cell phones, personalcomputers, automobiles, industrial control systems, aircraft, etc.

Unless specified otherwise, the various materials, substances,compositions, etc. described herein may be formed with any suitablemethodologies, either now known or yet to be developed, including, forexample, atomic layer deposition (ALD), chemical vapor deposition (CVD),physical vapor deposition (PVD), etc.

The terms “dielectric” and “insulative” may be utilized to describematerials having insulative electrical properties. The terms areconsidered synonymous in this disclosure. The utilization of the term“dielectric” in some instances, and the term “insulative” (or“electrically insulative”) in other instances, may be to providelanguage variation within this disclosure to simplify antecedent basiswithin the claims that follow, and is not utilized to indicate anysignificant chemical or electrical differences.

The terms “electrically connected” and “electrically coupled” may bothbe utilized in this disclosure. The terms are considered synonymous. Theutilization of one term in some instances and the other in otherinstances may be to provide language variation within this disclosure tosimplify antecedent basis within the claims that follow.

The particular orientation of the various embodiments in the drawings isfor illustrative purposes only, and the embodiments may be rotatedrelative to the shown orientations in some applications. Thedescriptions provided herein, and the claims that follow, pertain to anystructures that have the described relationships between variousfeatures, regardless of whether the structures are in the particularorientation of the drawings, or are rotated relative to suchorientation.

The cross-sectional views of the accompanying illustrations only showfeatures within the planes of the cross-sections, and do not showmaterials behind the planes of the cross-sections, unless indicatedotherwise, in order to simplify the drawings.

When a structure is referred to above as being “on”, “adjacent” or“against” another structure, it can be directly on the other structureor intervening structures may also be present. In contrast, when astructure is referred to as being “directly on”, “directly adjacent” or“directly against” another structure, there are no interveningstructures present. The terms “directly under”, “directly over”, etc.,do not indicate direct physical contact (unless expressly statedotherwise), but instead indicate upright alignment.

Structures (e.g., layers, materials, etc.) may be referred to as“extending vertically” to indicate that the structures generally extendupwardly from an underlying base (e.g., substrate). Thevertically-extending structures may extend substantially orthogonallyrelative to an upper surface of the base, or not.

Some embodiments include an arrangement having a first tier whichincludes a first set of memory cells on one side of a coupling region,and a second set of memory cells on an opposing side of the couplingregion. A first series of sense/access lines are under the memory cellsof the first and second sets, and are electrically connected with thememory cells of the first and second sets. A conductive interconnect iswithin the coupling region of the memory tier. A sense/access line of asecond series extends across the memory cells of the first and secondsets, and across the conductive interconnect. The sense/access line ofthe second series has a first region of a first composition, and has asecond region of a second composition. The first region is over thememory cells of the first and second series, and is electricallyconnected with the memory cells of the first and second series. Thesecond region is over the conductive interconnect and is electricallycoupled with the conductive interconnect. A second tier is verticallyoffset from the first tier. The second tier includes circuitry which iscoupled with the conductive interconnect.

Some embodiments include an arrangement having a memory tier whichincludes a first set of memory cells on one side of a coupling region,and a second set of memory cells on an opposing side of the couplingregion. A first series of sense/access lines are under the memory cellsof the first and second sets, and are electrically connected with thememory cells of the first and second sets. A conductive interconnect iswithin the coupling region of the memory tier. A sense/access line of asecond series extends across the memory cells of the first and secondsets, and across the conductive interconnect. The sense/access line ofthe second series has a first region having a second conductive materialover a first conductive material, and has a second region having onlythe second conductive material. The first region is over the memorycells of the first and second series and is electrically connected withthe memory cells of the first and second series. The second region isover the conductive interconnect and is electrically coupled with theconductive interconnect. An additional tier is under the memory tier.The additional tier includes CMOS circuitry which is coupled with theconductive interconnect.

Some embodiments include a method of forming an arrangement. An assemblyis formed to comprise, along a cross-section, a first set of memorycells on one side of a coupling region, and a second set of memory cellson an opposing side of the coupling region. An intervening insulativematerial is within the coupling region. The memory cells of the firstand second sets are over a first series of sense/access lines. Aconductive interconnect is formed within the coupling region and extendsthrough the intervening insulative material. A first conductive materialis formed to extend across the memory cells of the first and secondsets, and across the conductive interconnect. The first conductivematerial directly contacts upper surfaces of the memory cells and anupper surface of the conductive interconnect. The first conductivematerial is removed from over the upper surface of the conductiveinterconnect, while remaining portions of the first conductive materialare left over the memory cells of the first and second sets. A secondconductive material is formed over the remaining portions of the firstconductive material and over the upper surface of the conductiveinterconnect. The first and second conductive materials are patternedinto a sense/access line of a second series.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

1. An arrangement, comprising: a first tier including a first set ofmemory cells on one side of a coupling region, and a second set ofmemory cells on an opposing side of the coupling region; a first seriesof sense/access lines under the memory cells of the first and secondsets, and electrically connected with the memory cells of the first andsecond sets; a conductive interconnect within the coupling region of thememory tier; a sense/access line of a second series extending across thememory cells of the first and second sets, and across the conductiveinterconnect; the sense/access line of the second series having a firstregion comprising a first composition, and having a second regioncomprising a second composition which is different than the firstcomposition; the first region being over the memory cells of the firstand second series and being electrically connected with the memory cellsof the first and second series; the second region being over theconductive interconnect and being electrically coupled with theconductive interconnect; and a second tier vertically offset from thefirst tier; the second tier comprising circuitry which is coupled withthe conductive interconnect.
 2. The arrangement of claim 1 wherein thecircuitry of the second tier is CMOS circuitry.
 3. The arrangement ofclaim 1 wherein the first composition includes two or more materials,and wherein the second composition includes a subset of the materials ofthe first composition.
 4. The arrangement of claim 3 wherein the secondcomposition has higher conductivity than the first composition.
 5. Thearrangement of claim 4 wherein the first composition includes an upperlayer over a lower layer, with the upper layer comprising one or more ofTa, Pt, Cu, W and Pd; and wherein the second composition comprises onlythe upper layer.
 6. The arrangement of claim 4 wherein the firstcomposition includes one or more of Ta, Pt, Cu, W and Pd over one ormore of carbon, WSiN, WN and TiN; and wherein the second compositionincludes only the one or more of Ta, Pt, Cu, W and Pd. 7-39. (canceled)